The invention relates to novel hydrocarbon oil compositions containing a hydrocarbon oil and a polymer additive.
Hydrocarbon oils such as gas oils, diesel oils, lubricating oils and crude oils can contain considerable amounts of paraffins. When these oils are stored, transported and used at low temperature, problems can occur as a result of crystallization of these paraffins. In order to minimize these problems, it is customary to add certain polymers to the paraffinic hydrocarbon oils. Very customary for this purpose are high-molecular copolymers of ethylene and vinyl acetate, which are commercially available under various names.
In an investigation by the Applicant concerning the use of polymers as additives in paraffinic hydrocarbon oils for improving the properties of these hydrocarbon oils at low temperature, a class of polymers has been found which have proved to be outstandingly suitable for lowering the pour point (PP), the cloud point (CP) and/or the cold filter plugging point (CFPP) of these oils. Comparison of the performance of these polymers with that of the above-mentioned ethylene/vinyl acetate copolymers shows that the former polymers possess a higher activity than these commercial additives. This means that, in comparison with these commercial additives, the polymers investigated by the Applicant for this purpose give--at equal concentration--a stronger PP, CP and/or CFPP reduction or alternatively that an equal PP, CP and/or CFPP reduction or alternatively that an equal PP, CP and/or CFPP reduction can be obtained at a lower concentration. These polymers are linear polymers of carbon monoxide with one or more .alpha.-olefins having at least 10 carbon atoms per molecule (below referred to as C.sub.10+ .alpha.-olefins) and optionally one or more C.sub.9+ or less olefin polymer comprising of substantially alternating monomer units of carbon monoxide and olefins. A number of the polymers found by the Applicant to be suitable as additives for paraffinic hydrocarbon oils were especially synthesized for this purpose and are novel compounds. These are polymers of carbon monoxide with one or more C.sub.10+ .alpha.-olefins, which polymers possess a mean molecular weight, calculated as mean weight (M.sub.w), of more than 10.sup.4. These polymers can be prepared by contacting the monomers, at elevated temperature and pressure and in the presence of a diluent consisting of more than 90%v of an aprotic liquid, with a catalyst composition containing a Group VIII metal and a phosphorous bidentate ligand having the general formula (R.sub.1 R.sub.2 P).sub.2 R, where R.sub.1 and R.sub.2 represent identical or different optionally polar substituted aliphatic hydrocarbon groups and R a bivalent organic bridging group containing at least two hydrocarbon atoms in the bridge linking the two phosphorous atoms together.